blat - Blat is a small, efficent SMTP command line mailer for Windows.
PowerMTA - PowerMTA is an industrial-strength software for high-volume email delivery.
CMail - CMail is a free Windows command line mailer with advanced message formatting options.
Postfix - Postfix is a mail transfer agent (MTA) that routes and delivers electronic mail.
sendEmail - sendEmail is a lightweight, command line SMTP email client.
EmailSuccess - EmailSuccess is an advanced MTA built to handle the most critical reliability, performance, security, and deliverability requirements.